Scroll compressor

ABSTRACT

In a rotating compressor, an outer peripheral surface ( 40 ) of a partition member ( 23 ) which is secured firmly to a casing ( 10 ) so as to divide the inside of the casing ( 10 ) into a high-level pressure space and a low-level pressure space, is provided with a peripheral groove ( 42 ) for allowing for shrinkage of the casing ( 10 ) at a weld area where a trunk part ( 11 ) and end plate ( 12 ) of the casing ( 10 ) are welded together. As a result of such arrangement, the partition member ( 23 ) is strongly tightened by making utilization of such shrinkage, thereby not only enhancing sealability between the high-level pressure space and the low-level pressure space in the inside of the casing ( 10 ) but also preventing a drop in workability during assembling and an increase in cost.

TECHNICAL FIELD

[0001] The present invention relates generally to a rotating compressorand, more particularly, pertains to a seal construction between ahigh-level pressure space and a low-level pressure space in the insideof a rotating compressor casing.

BACKGROUND ART

[0002] Various types of compression mechanisms such as scroll type,swing type, and rolling piston type (i.e., rotary type) have beenemployed in conventional rotating compressors. Such a rotatingcompressor is used to compress a refrigerant gas in a refrigeratingapparatus (e.g., an airconditioner) which executes a refrigeratingcycle, as set forth for example in Japanese Patent Kokai No.(2000)97183. A compressor motor, housed in the rotating compressor,serves as a drive source for activating a compression mechanism of thescroll, swing, or rolling piston type.

[0003] Here, referring to a scroll compressor (100) of FIG. 10 as anexample, a general structure of a conventional rotating compressor willbe described below.

[0004] The scroll compressor (100) is made up of a casing (101), acompressor motor (102), and a compression mechanism (103). The casing(101) is made up of a trunk part (104) shaped like a cylinder and endplates (105, 106) secured firmly, by welding, to an upper and lower endsof the trunk part (104), respectively. The compressor motor (102) ismade up of a stator (107) secured firmly to the trunk part (104) and arotor (108) disposed on the inner peripheral side of the stator (107). Adrive shaft (109) is coupled to the rotor (108).

[0005] The compression mechanism (103) has a fixed scroll, an orbitingscroll, and a housing all of which are not shown in the Figure, and thehousing is secured firmly to the casing. In some cases, the fixed scrollis secured firmly to the casing. Additionally, the drive shaft (109)projects above and below the stator (107) and the rotor (108). An upperend of the drive shaft (109) is connected to the orbiting scroll. On theother hand, a lower end of the drive shaft (109) is supported, through abearing member (110), on the casing (101). Operations of the orbitingscroll accompanying the rotation of the drive shaft (109) causevariations in volume of a compression chamber, whereby the compressionmechanism (103) performs operations of sucking, compressing, anddischarging a refrigerant gas.

[0006] In the scroll compressor (100), the housing of the compressionmechanism (103) is close-fitted, at its outer peripheral part, to thecasing (101), thereby defining spaces separated from each other, i.e., aspace above the compression mechanism (103) and another below thecompression mechanism (103), as set forth for example in Japanese PatentKokai No. (1999)22661. In the example diagrammed, the lower space is ahigh-level pressure space, while the upper space is a low-level pressurespace. These spaces are sealed off from each other at a joint area (111)between the casing (101) and the housing. In such an arrangement, thehousing functions as a partition member.

[0007] Problems that Invention Intends to Solve

[0008] In the conventional scroll compressor, generally the housing issecured firmly to the casing by thermal insert. Although thermal insertprovides a structure of high sealability, it suffers problems withworkability during the time that products are being assembled.

[0009] By contrast to the above, there may be an alternative structurein which the housing is secured firmly to the casing only by pressfitting. In this case, workability is improved in comparison with astructure of the thermal insert type; however, there is the possibilitythat sealability decreases and, as a result, refrigerant leaks from thehigh-level pressure space to the low-level pressure space. Use of aspecial seal member for enhancing sealability results in increasing thecosts.

[0010] Bearing in mind these problems, the present invention was made.Accordingly, an object of the present invention is to enhance not onlyworkability during compressor assembling but also sealability between ahigh-level pressure space and a low-level pressure space in a casing ina rotating compressor, and to prevent the increase in costs.

DISCLOSURE OF INVENTION

[0011] In the present invention, a peripheral groove (42) for allowingfor shrinkage of a casing (10) at a weld area where a trunk part (11) ofthe casing (10) and an end plate (12) are welded together, is formed inan outer peripheral surface (40) of a partition member (23) dividing theinside of the casing (10) into a high-level pressure space and alow-level pressure space, and the partition member (23) is tightened bymaking utilization of such shrinkage.

[0012] More specifically, an invention as set forth in claim 1 isdirected to a rotating compressor comprising a casing (10) housingtherein: a compressor motor (30), a compression mechanism (20) which isdriven by the compressor motor (30), and a partition member (23) whichdivides the inside of the casing (10) into a high-level pressure spaceand a low-level pressure space, the casing (10) having a trunk part (11)shaped like a cylinder and an end plate (12) secured firmly to the trunkpart (11) by welding.

[0013] The rotating compressor is characterized in that the partitionmember (23) is so formed as to be press-fitted to the casing (10) at aweld area where the trunk part (11) and the end plate (12) are weldedtogether or in the vicinity of the weld area, and a peripheral groove(42) extending continuously in a circumferential direction for allowingfor shrinkage of the casing (10) caused by welding at the weld area ofthe trunk part (11) and the end plate (12) is formed in an outerperipheral surface (40) of the partition member (23).

[0014] The “partition member (23)” of this structure may be a member towhich a fixed scroll is attached or a fixed scroll itself for the caseof a scroll compressor. The partition member (23) may be any member aslong as it divides the inside of a casing into a high-level pressurespace and a low-level pressure space, even for the case of a rotary orswing compressor.

[0015] In the invention as set forth in claim 1, when the trunk part(11) and the end plate (12) are welded together with the partitionmember (23) close-fitted, by press fitting, to the casing (10) (eitherthe trunk part (11) or the end plate (12)), the welding of the trunkpart (11) and the end plate (12) causes the casing (10) to shrink at theperipheral groove (42) of the outer peripheral surface (40) of thepartition member (23). Prior to welding, the partition member (23) ismerely press-fitted to the casing (10); however, the act of weldingcauses the casing (10) to strongly tighten the partition member (23) inthe vicinity of the peripheral groove (42), thereby making it possibleto provide sealability of the same level that thermal insert provides.

[0016] An invention as set forth in claim 2 according to the rotatingcompressor of claim 1 is characterized in that a projection part(45)(46, 47) extending continuously in a circumferential direction at aposition in proximity to the peripheral groove (42) is formed in theouter peripheral surface (40) of the partition member (23), and that theprojection part (45)(46, 47) is so formed as to be press-fitted to thecasing (10).

[0017] In such arrangement, the trunk part (11) and the end plate (12)are welded together, with the projection part (45)(46, 47) formed in theouter peripheral surface (40) of the partition member (23) press-fittedto the casing (10) (either the trunk part (11) or the end plate (12)),thereby producing the same action as obtained by further increasing themargin for press-fitting of the projection part (45)(46, 47) to thetrunk part (11) or to the end plate (12), and the sealability isimproved.

[0018] In an invention as set forth in claim 3, the outer peripheralsurface (40) of the partition member (23) is clearance-fitted to thetrunk part (11) or end plate (12) of the casing (10), and the peripheralgroove (42) and the projection part (45)(46, 47) are formed in the outerperipheral surface (40) of the partition member (23).

[0019] In other words, this invention is characterized in that thepartition member (23) is so formed as to be clearance-fitted to thecasing (10) at a weld area where the trunk part (11) and the end plate(12) are welded together or in the vicinity of the weld area, that theperipheral groove (42) extending continuously in circumferentialdirection for allowing for shrinkage of the casing (10) caused bywelding at the weld area of the trunk part (11) and the end plate (12),and the projection part (45)(46, 47) extending continuously incircumferential direction at a position in proximity to the peripheralgroove (42) are formed in the outer peripheral surface (40) of thepartition member (23), and that the projection part (45)(46, 47) is soformed as to be press-fitted to the casing (10).

[0020] In the invention as set forth in claim 3, when the trunk part(11) and the end plate (12) are welded together, with the partitionmember (23) press-fitted to the trunk part (11) or end plate (12) of thecasing (10) only at the projection part (45)(46, 47), the casing (10)shrinks at the position of the peripheral groove (42) and its tighteningforce becomes greater. Accordingly, this structure also providessealability of the same level that thermal insert achieves.

[0021] Further, an invention as set forth in claim 4 according to therotating compressor of either claim 2 or claim 3 is characterized inthat the projection part (46, 47) of the partition member (23) isprovided at a plurality of areas.

[0022] In such an arrangement, the projection part (46, 47) extendingcontinuously in a circumferential direction in the outer peripheralsurface (40) of the partition member (23) is provided in multiple in theaxial direction of the partition member (23), thereby providing anenhanced sealability because the number of points where the projectionpart (46, 47) is press-fitted to the trunk part (11) or to the end plate(12) increases.

[0023] A fifth invention as set forth in claim 5 according to therotating compressor of claim 4 is characterized in that the projectionparts (46, 47) differ in projection height from each other.

[0024] In such an arrangement, for example, it becomes possible to makethe projection height of a projection part (46, 47) on the forward siderelative to the direction of press-fitting the partition member (23) tothe trunk part (11) or to the end plate (12) shorter than the projectionheight of a projection part (46, 47) on the rearward side relative tothe press-fitting direction. This makes it possible to press-fit thepartition member (23) to the casing (10) with relative ease and, inaddition, there is no drop in sealability.

[0025] Further, an invention as set forth in claim 6 according to therotating compressor of either claim 2 or 3 is characterized in that oneend or both ends (45 a, 45 b) of the projection part (45)(46, 47)relative to the axial direction of the partition member (23) are formedinto a tapered surface.

[0026] In the invention of claim 6, if, of the ends of the projectionpart (45)(46, 47), a forward side end relative to the direction ofpress-fitting the partition member (23) to the trunk part (11) or to theend plate (12) is formed into a tapered surface (45 a), press-fitting ofthe partition member (23) to the casing (10) becomes easy to carry out.In addition, if, of the ends of the projection part (45)(46, 47), arearward side end relative to the press-fitting direction is formed intoa tapered surface (45 b), this makes it easier, when the casing (10)shrinks along the tapered surface (45 b) at a weld area where the trunkpart (11) and the end plate (12) are welded together, for such ashrinking area of the casing (10) to come into press-contact with thetapered surface (45 b). If press-contacting of the projection part(45)(46, 47) with the casing (10) is insufficient, there is thepossibility that the sealability drops. By contrast to this, in theinvention of claim 6, it is possible to provide a sufficientpress-contacting surface, thereby improving the sealability.

[0027] An invention as set forth in claim 7 according to the rotatingcompressor of either claim 2 or claim 3 is characterized in that thepartition member (23) has a thick and thin parts (43) and (44) ofdifferent thicknesses relative to a radial direction, and that theprojection part (45)(46, 47) is formed on an outer periphery of thethick part (43). In this arrangement, the thick part (43) is a partwhose radial dimension is thick throughout, while the thin part (44) isa part which partially includes at least a thin subpart.

[0028] Although the casing (10) strongly tightens the partition member(23) at the time when it shrinks because of welding, the formation ofthe projection part (45)(46, 47) on the outer periphery of the thickpart (43) of the partition member (23) makes it possible to oppose sucha tightening force with the rigidity of the thick part (43).Consequently, it is possible to prevent the partition member (23) fromundergoing deformation or the like.

[0029] An invention as set forth in claim 8 according to the rotatingcompressor of any one of claims 1-3 is characterized in that the endplate (12) of the casing (10) comes into axial abutment against thetrunk part (11) or the partition member (23) and is so formed as to beclearance-fitted to the trunk part (11) or the partition member (23).

[0030] With such an arrangement, the partition member (23) is securedfirmly to the casing (10) with ease and without fail by welding togetherthe end plate (12) and the trunk part (11) while easily positioning theend plate (12) to the casing (10) in its axial direction.

[0031] An invention as set forth in claim 9 according to the rotatingcompressor of any one of claims 1-3 is characterized in that thecompression mechanism (20) is composed of a scroll type compressionmechanism (20), and that the partition member (23) is such formed that afixed scroll (21) is secured firmly to the partition member (23).

[0032] By contrast to the above, when the fixed scroll (21) itself isfirmly secured, by thermal insert or the like, to the casing (10) so asto serve as the partition member (23) in the scroll compressor, there isthe possibility that the fixed scroll (21) undergoes deformation and theperformance of the compressor drops, depending on the relationshipbetween the strength of the fixed scroll (21) and the tightening force.However, in the present invention it is arranged such that the partitionmember (23) formed as a separate body from the fixed scroll (21) issecured firmly to the casing (10). As a result of such arrangement, notightening force acts on an involute part of the fixed scroll (21) andthere occurs no compressor performance decrement.

[0033] Effects

[0034] In accordance with the invention as set forth in claim 1, theouter peripheral surface (40) of the partition member (23) which isbrought into close-fit with the trunk part (11) or end plate (12) of thecasing (10) is provided with the peripheral groove (42) for enabling thecasing (10) to shrink by welding at a weld area of the trunk part (11)and the end plate (12), thereby making it possible to strongly tightenthe partition member (23) by utilizing such shrinkage. This providesenhanced sealability at the joint area of the casing (10) and thepartition member (23). Accordingly, even for the case where thepartition member (23) is merely press-fitted to the casing (10), it ispossible to obtain sealability of the same level that thermal insertprovides after welding was carried out. Besides, since thermal insert isactually unnecessary, this provides an excellent workability duringassembling. Further, in such an arrangement that the trunk part (11) andthe end plate (12) are welded together after the partition member (23)is thermal-inserted to the trunk part (11), there is the possibilitythat component parts undergo distortion due to repeated heating.However, in the present invention heating is carried out only once, sothat the possibility of distortion of component parts is slim.

[0035] Furthermore, conventional compressors employ an O-ring in somecases for obtaining enhanced sealability. In such a case, the costsincreases. However, in the aforesaid arrangement, there is no need forthe provision of a special seal member such as an O-ring, therebyavoiding the increase in costs due to the increase in the number ofcomponent parts.

[0036] Further, in accordance with the invention as set forth in claim2, the projection part (45)(46, 47) in close proximity to the peripheralgroove (42) is formed in the outer peripheral surface (40) of thepartition member (23) and the projection part (45)(46, 47) ispress-fitted to the trunk part (11) or end plate (12) of the casing(10), whereby sealability is further enhanced by the effect of shrinkageof the trunk part (11).

[0037] Further, in accordance with the invention as set forth in claim3, the outer peripheral surface (40) of the partition member (23) isclearance-fitted to the trunk part (11) or end plate (12) of the casing(10), wherein the peripheral groove (42) and the projection part(45)(46, 47) are formed in the outer peripheral surface (40) of thepartition member (23). Because of such arrangement, it will suffice ifonly the projection part (45)(46, 47) is press-fitted to the casing(10), thereby facilitating assembling work. In addition, since thecasing (10) strongly tightens only the projection part (45)(46, 47),this avoids application of a strong tightening force to the whole of thepartition member (23). Accordingly, deformation of the partition member(23) is also prevented. Furthermore, sealability is improved and theincrease in costs due to the increase in the number of component partsis prevented, as in the inventions of claims 1 and 2.

[0038] Further, in accordance with the invention as set forth in claim4, the projection part (46, 47) extending continuously in acircumferential direction in the outer peripheral surface (40) of thepartition member (23) is provided at a plurality of areas, for obtaininga multiple seal effect in axial direction. This provides a furtherenhanced sealability.

[0039] Furthermore, in accordance with the invention as set forth inclaim 5, it is arranged such that the projection parts (46, 47) differin projection height from each other. For example, it becomes possibleto make the projection height of one of the projection parts (46, 47) onthe forward side relative to the direction of press-fitting thepartition member (23) to the casing (10) shorter than the projectionheight of the other of the projection parts (46, 47) on the rearwardside relative to the press-fitting direction. This makes it possible toclose-fit the partition member (23) to the casing (10) with relativeease. In other words, workability is enhanced to a further extentwithout a drop in sealability.

[0040] Further, in accordance with the invention as set forth in claim6, it is arranged such that one end or both ends (45 a, 45 b) of theprojection part (45)(46, 47) relative to the axial direction of thepartition member (23) are formed into a tapered surface. Of the ends ofthe projection part (45) (46, 47), one end on the forward side relativeto the direction of press-fitting the partition member (23) to thecasing (10) is formed into the tapered surface (45 a). This facilitatesinsertion and enhances workability. Conversely, if the other end of theprojection part (45)(46, 47) on the rearward side relative to thepress-fitting direction is formed into the tapered surface (45 b), thetrunk part (11) comes into press contact with the tapered surface.Accordingly, it is possible to obtain an adequate sealability.

[0041] Furthermore, in accordance with the invention as set forth inclaim 7, the partition member (23) has the thick and thin parts (43) and(44) of different thicknesses in a radial direction, wherein theprojection part (45)(46, 47) is formed on the outer periphery of thethick part (43) of high rigidity. As a result of such arrangement, evenwhen the trunk part (11) shrinks because of welding, deformation of thepartition member (23) is prevented. Accordingly, for example, even whenthe fixed scroll (21) as a partition member is secured firmly to thecasing (10) in the scroll compressor, it is possible to preventperformance decrement of the compressor caused by deformation of thefixed scroll (21).

[0042] Further, in accordance with the invention as set forth in claim8, the end plate (12) of the casing (10) comes into axial abutmentagainst the trunk part (11) or the partition member (23) of thecompression mechanism (20) and is so formed as to be clearance-fitted tothe trunk part (11) or to the partition member (23). Accordingly, thepartition member (23) is secured firmly to the casing (10) without failby welding together the end plate (12) and the trunk part (11) whileeasily positioning the end plate (12) to the casing (10), therebyimproving workability.

[0043] In accordance with the invention as set forth in claim 9, in thescroll compressor the member to which the fixed scroll is secured firmlyis the partition member (23), and the partition member (23) is tightenedby making utilization of shrinkage caused by welding of the trunk part(11) and the end plate (12). Accordingly, since such a tightening forcewill not act directly on the fixed scroll, this prevents performancedecrement by leakage loss due to involute wrap deformation. It isconceivable that an elastic member capable of absorbing deformation ofthe partition member (23) is interposed between the fixed scroll and thecasing (10) in a conventional structure for suppressing leakage loss. Insuch a case, however, the number of component parts increases, and thereis a drop in assembling property and the costs increases. The presentinvention is free from such problems.

BRIEF DESCRIPTION OF DRAWINGS

[0044]FIG. 1 is a view illustrating in cross section a construction of ascroll compressor according to a first embodiment of the presentinvention;

[0045]FIG. 2, which is a partially enlarged view of the scrollcompressor of FIG. 1, illustrates a seal construction between ahigh-level pressure space and a low-level pressure space in the insideof a casing;

[0046]FIG. 3 is an enlarged view of a projection part of a housing;

[0047]FIG. 4 is a view showing a modification example of a weld areawhere a trunk part and an end plate of the casing are welded together;

[0048]FIG. 5 depicts a first modification example of the projectionpart;

[0049]FIG. 6 depicts a second modification example of the projectionpart;

[0050]FIG. 7 depicts a third modification example of the projectionpart;

[0051]FIG. 8 depicts a fourth modification example of the projectionpart;

[0052]FIG. 9 is a partially enlarged view showing a seal construction ofa scroll compressor according to a second embodiment of the presentinvention; and

[0053]FIG. 10 is a view illustrating in cross section a conventionalscroll compressor.

BEST MODE FOR CARRYING OUT INVENTION FIRST EMBODIMENT

[0054] Hereinafter, a first embodiment of the present invention will bedescribed in detail with reference to the drawings.

[0055] The present embodiment is directed to a scroll compressor. In thefirst place, the entire arrangement of the scroll compressor of thefirst embodiment will be described with reference to FIG. 1.

[0056] The scroll compressor (1) of the first embodiment is used tocompress a low-level pressure refrigerant drawn in from the side of anevaporator and discharge it to the side of a condenser in a refrigerantcircuit of an airconditioner or other device which performs a vaporcompression refrigerating cycle. As shown in FIG. 1, the scrollcompressor (1) comprises a casing (10) housing therein a compressionmechanism (20) and a compressor motor (30) which is a drive mechanismoperable to activate the compression mechanism (20). The compressionmechanism (20) is disposed at an upper portion of the inside of thecasing (10), while the compressor motor (30) is disposed at a positionslightly below the center of the inside of the casing (10).Additionally, the casing (10) is provided with a connector terminal (35)for supplying electric power to the compressor motor (30).

[0057] The casing (10) is made up of a trunk part (11) shaped like acylinder and dish-shaped end plates (12, 13) secured firmly to an upperand lower ends of the trunk part (11) or to their vicinitiesrespectively by welding. A suction pipe (14) is so disposed as to passthrough the upper end plate (12) of the casing (10). A discharge pipe(15) passing through the trunk part (11) is disposed at a positionslightly above the center of the trunk part (11) so that it communicateswith both the inside and the outside of the casing (10). Additionally,it is arranged such that a given amount of lubricant (refrigeratingmachine oil) (not shown) is stored at the bottom of the casing (10).

[0058] The compressor motor (30) is made up of a stator (31) securedfirmly to the trunk part (11) of the casing (10) and a rotor (32)disposed on the inner side of the stator (31), and a drive shaft (33) issecured firmly to the rotor (32) of the motor (30). The drive shaft (33)projects vertically relative to the stator (31) and the rotor (32) ofthe compressor motor (30). An upper end of the drive shaft (33) isconnected to the compression mechanism (20), while a lower end thereofis rotatably supported on a bearing member (34) secured firmly to thelower end of the trunk part (11) of the casing (10).

[0059] On the other hand, the compression mechanism (20) comprises afixed scroll (21), an orbiting scroll (22), and a housing (23). Thefixed scroll (21) is made up of an end plate (21 a) and an involute wrap(21 b) formed in a lower surface of the end plate (21 a). The orbitingscroll (22) is made up of an end plate (22 a) and an involute wrap (22b) formed in an upper surface of the end plate (22 a).

[0060] The housing (23) constitutes a part of the compression mechanism(20), and the position of the compression mechanism (20) is fixed byfirmly securing the housing (23) to the casing (10) by press fitting.The housing (23) is a partition member dividing the internal space ofthe casing (10) into an upper space and a lower space. Morespecifically, a low-level pressure space is defined above the housing(23) and a high-level pressure space is defined below the housing (23).

[0061] The fixed scroll (21) is fastened firmly to an upper surface ofthe housing (23) by a fastening means such as a bolt (not shown). Theorbiting scroll (22) is disposed between the fixed scroll (21) and thehousing (23). Additionally, a rotation preventing member (24) such as anOldham joint is disposed between the end plate (22 a) of the orbitingscroll (22) and the housing (23) so that the orbiting scroll (22)executes only an orbital motion relative to the fixed scroll (21).

[0062] The wrap (21 b) of the fixed scroll (21) and the wrap (22 b) ofthe orbiting scroll (22) matingly engage with each other. Between theend plate (21 a) of the fixed scroll (21) and the end plate (22 a) ofthe orbiting scroll (22), a space between contacting parts of the wraps(21 b, 22 b) is formed as a compression chamber (25). The compressionchamber (25) is so structured as to compress refrigerant as the volumebetween the wraps (21 b, 22 b) shrinks toward the center with therevolution of the orbiting scroll (22).

[0063] In the end plate (21 a) of the fixed scroll (21), a suctionopening (21 c) for low-level pressure refrigerant is formed at aperipheral edge of the compression chamber (25). On the other hand, inthe end plate (22 a) of the orbiting scroll (22), a discharge opening(22 c) for high-level pressure refrigerant is formed centrally in thecompression chamber (25). The suction pipe (14) secured firmly to theend plate (12) of the casing (10) is connected to the refrigerantsuction opening (21 c). Connected to the suction pipe (14) is anevaporator of the refrigerant circuit (not shown).

[0064] A boss (22 d) to which an upper end part (33 a) of the driveshaft (33) is connected is formed centrally in the lower surface of theend plate (22 a) of the orbiting scroll (22). In the drive shaft (33),its upper end part (33 a) is an eccentric shaft portion deviating fromthe rotational center of the drive shaft (33), and the drive shaft (33)is rotatably supported, at a position immediately below the eccentricshaft portion (33 a), on the housing (23). In addition, a seal ring(26), disposed around the boss (22 d), engages with an inner aperture(23 a) of the housing (23), and it is arranged such that refrigerant gasat a high-level pressure introduced to the inner aperture (23 a) willnot leak to the outer peripheral side beyond the seal ring (26).

[0065] A discharge path (27), for guiding a high-level pressurerefrigerant from the discharge opening (22 c) of the orbiting scroll(22) to a space below the housing (23), is formed in the drive shaft(33). A lower end of the discharge path (27) opens at a position belowthe compressor motor (30). The high-level pressure refrigerant gasflowing out of the discharge path (27) is supplied from the dischargepipe (15) disposed in the trunk part (11) of the casing (10) to acondenser of the refrigerant circuit through a refrigerant pipe (notshown).

[0066] The drive shaft (33) is provided with a lubrication pump (28) anda lubrication path (33 b). The lubrication pump (28) is disposed at alower end part of the drive shaft (33) and is so constructed as to drawlubricant (not shown) stored at the bottom of the casing (10) with therevolution of the drive shaft (33). The lubrication path (33 b) extendsvertically in the inside of the drive shaft (33) and communicates withlubrication openings (not shown) formed at each part so that lubricantdrawn by the lubrication pump (28) is supplied to each sliding part.

[0067] In the above-described arrangement, the rotor (32) startsrotating when the motor (30) is activated, and, as a result, the driveshaft (33) rotates. When the drive shaft (33) rotates, the orbitingscroll (22) does not rotate on its axis but executes only an orbitalmotion relative to the fixed scroll (21). As a result of this, with thevariation in volume of the compression chamber (25), low-level pressurerefrigerant is sucked in to a peripheral edge part of the compressorchamber (25) from the suction pipe (14). And the refrigerant iscompressed. The refrigerant, which has now become high in pressurelevel, flows through the discharge path (27) and fills up a space belowthe housing (23) within the casing (10). After being discharged from thedischarge pipe (15), the refrigerant is subjected to a condensationprocess, an expansion process, and an evaporation process in therefrigerant circuit and, thereafter, is again sucked in from the suctionpipe (14) for compression, which is carried out repeatedly.

[0068] As has been described above, the housing (23) vertically compartsthe internal space of the casing (10). The first embodiment ischaracterized in that the housing (23) itself has a function ofproviding sealing between the low-level pressure space above the housing(23) and the high-level pressure space below the housing (23). Referringto FIGS. 2 and 3, such a seal construction will be described below.

[0069]FIG. 2, which is an enlarged cross-sectional view of the sealconstruction, shows that the housing (23) is dimension-structured suchthat an outer peripheral surface (40) of the housing (23) is securedfirmly to the trunk part (11) of the casing (10) by press fitting.Formed at an upper end part of the housing (23) is a collar part (41)which projects radially outwardly so as to abut against an upper endsurface of the trunk part (11). Additionally, formed in the outerperipheral surface (40) of the housing (23) is a peripheral groove (42)extending continuously in a circumferential direction for allowing forshrinkage of the casing (10) caused by welding at a weld area where thetrunk part (11) and the end plate (12) are welded together. Theperipheral groove (42) is formed at a position immediately below thecollar part (41) in the outer peripheral surface (40) of the housing(23).

[0070] The housing (23) has a thick and thin parts (43) and (44) ofdifferent thicknesses relative to a radial direction. The thick part(43) is a thick part whose radial dimension is constant throughout. Thethin part (44) is a part which partially includes at least a thinsubpart.

[0071] The outer peripheral surface (40) of the housing (23) isprovided, at a position in close proximity to the lower end of theperipheral groove (42), with a projection part (45) continuouslyextending in a circumferential direction, and the projection part (45)is located on the outer periphery of the thick part (43). The projectionpart (45) is so formed as to be press-fitted to the trunk part (11) ofthe casing (10), and, as shown in FIG. 3 which is an enlarged view ofthe projection part (45), its axial (upper and lower) ends (45 a, 45 b)are each formed into a tapered surface. Of these tapered surfaces of theprojection part, the tapered surface (45 a) on the press-fitting side(lower side) relative to the trunk part inclines at an angle of about 15degrees with respect to the outer peripheral surface (40) of the housing(23). Additionally, the tapered surface (45 b) on the side (upper side)opposite to the press-fitting side inclines at an angle of about 45degrees with respect to the outer peripheral surface (40) of the housing(23).

[0072] The upper end plate (12) of the casing (10) is such formed thatit abuts against the housing (23) in an axial direction and isclearance-fitted to the trunk part (11) and the housing (23) in a radialdirection. In other words, the position of the end plate (12) is locatedaxially with respect to the trunk part (11) and the housing (23), but isnot located radially at this portion. Because of this, assembling workduring welding of the trunk part (11) and the end plate (12) becomeseasy to perform.

[0073] In the above-described seal construction, the housing (23) of thecompression mechanism (20) is press-fitted to the trunk part (11) untilthe collar part (41) comes into abutment against the upper end surfaceof the trunk part (11), and, thereafter, the end plate (12) is welded tothe trunk part (11), whereby the compression mechanism (20) is locatedsecurely within the casing (10) and the high-level pressure space andthe low-level pressure space are sealed off from each other.

[0074] Stated another way, the housing (23) is press-fitted to the trunkpart (11), as shown in FIG. 2(a). As a result, the outer peripheralsurface (40) of the housing (23) comes into press contact with the innerperipheral surface of the trunk part (11) and the projection part (45)cuts into the inner peripheral surface of the trunk part (11).Thereafter, when, as shown in FIG. 2(b), the end plate (12) is welded tothe trunk part (11), the trunk part (11) shrinks at the position of theperipheral groove (42) after welding (after cooling), and the trunk part(11) strongly tightens the housing (23) in a region at least from theperipheral groove (42) to the area immediately therebelow. This producesthe same action as obtained by increasing the margin for press-fittingof the outer peripheral surface (40) and the projection part (45) of thehousing (23) with respect to the trunk part (11), thereby providingenhanced seal effects. In addition to the arrangements that the housing(23) is merely press-fitted to the trunk part (11) and the projectionpart (45) cuts into to the trunk part (11), post-welding shrinkage ofthe trunk part (11) is utilized, thereby making it possible to enhancesealability to the same level as does thermal insert.

[0075] As stated above, the present embodiment provides the samesealability as thermal insert does. In the present embodiment, however,thermal insert is practically unnecessary. Moreover, since sealabilityis enhanced by making utilization of welding of the trunk part (11) andthe end plate (12) which is an operation to be done inevitably for thecompressor (1) of such a type, this eliminates the need for performingany other additional operations for seal function, and workability atassembling time is at the same level as when only press-fitting iscarried out, and is excellently good.

[0076] In an arrangement that the trunk part (11) and the end plate (12)are welded together after thermal insert of the housing (23) to thetrunk part (11), heating is carried out repeatedly thereby producing thepossibility that component parts undergo distortion. By contrast tothis, in the present invention heating is carried out only once.Therefore the possibility that component parts undergo distortion isslim.

[0077] Further, as a seal construction, a special seal member such as anO-ring has generally been used in the prior art. However, the firstembodiment eliminates the need for the provision of a component partdedicated for sealing such as an O-ring. Therefore, the number ofcomponent parts for seal function will not increase and, therefore, theincrease in costs will not occur.

[0078] Further, since one end of the projection part (45) on the forwardside relative to the direction of press-fitting to the trunk part (11)is formed into the tapered surface (45 a), this facilitatespress-fitting of the housing (23) to the casing (10). Moreover, theother end of the projection part (45) on the rearward side relative tothe press-fitting direction is formed into the tapered surface (45 b)and, as a result of such arrangement, when the trunk part (11) shrinksalong the tapered surface (45 b) at a weld area where the trunk part(11) and the end plate (12) are welded together, such a shrinking areacomes into press contact with the tapered surface (45 a), thereby makingit possible to provide sufficient sealability. In other words,insufficient press-contacting of this part with the tapered surface (45a) may cause a decrease in sealability. By contrast to this, in thepresent embodiment the shrinking area is brought into sufficient presscontact with the tapered surface (45 a) thereby improving sealability.

[0079] Additionally, in the present embodiment the projection part (45)is formed on the outer periphery of the thick part (43) of the housing(23) and, as a result of such arrangement, it becomes possible for thethick part (43) to sufficiently resist forces strongly tightening thehousing (23) produced when the casing (10) shrinks by welding.Accordingly, even when the casing (10) shrinks, the housing (23) willundergo no deformation.

[0080] Further, in the present embodiment: the housing (23) to which thefixed scroll (21) is firmly secured is press-fitted to the trunk part(11); the projection part (45) is formed in the outer peripheral surface(40) of the housing (23); and the housing (23) is tightened by the trunkpart (11) so that the high-level pressure space and the low-levelpressure space are sealed off from each other, whereby tightening forcesproduced when the casing (10) shrinks will not act directly on the fixedscroll (21). Consequently, the wrap (21 b) of the fixed scroll (21) willnot deform and the decrement in performance of the compressor (1) due torefrigerant leakage or the like will not take place.

First Modification Example

[0081] In the first embodiment the casing (10) is such constructed thatthe end plate (12) is engaged by clearance fitting with the trunk part(11) and the outer periphery of the housing (23). However, the end plate(12) may be formed so as to fit into the inner peripheral side of thetrunk part (11) of the casing (10), and the peripheral groove (42) ofthe housing (23) may be formed such that it enables the end plate (12)to shrink by welding, as shown in FIG. 4. To sum up, the peripheralgroove (42) of the housing (23) may receive any one of the trunk part(11) and the end plate (12) as long as the casing (10) is constructed soas to strongly tighten the housing (23) by allowing the casing (10) toshrink at a weld area where the trunk part (11) and the end plate (12)are welded together. Also in the arrangement described above, it ispossible to provide the same effects as does the first embodiment.

Second Modification Example

[0082] The second modification example is a modification example of theprojection part.

[0083] In an example shown in FIG. 5, only the lower end part (45 a) ofthe projection part (45) which is a side to be press-fitted to the trunkpart (11) is formed into a tapered surface, and the upper end part (45b) is formed into a shape which rises perpendicularly from the outerperipheral surface (40) of the housing (23). Additionally, by contrastto the first embodiment in which the upper end part (45 b) of theprojection part (45) is a tapered surface which connects directly to theperipheral groove (42), FIG. 6 shows an example in which only an area ofthe end part (45 b) extending from the outer peripheral end of theprojection part (45) to the outer peripheral surface (40) of the housing(23) is formed into a tapered surface. Besides, FIG. 7 illustrates anexample in which neither the upper end part (45 b) nor the lower endpart (45 a) of the projection part (45) is formed into a taperedsurface. In the example the upper end part (45 b) and the lower end part(45 a) are end surfaces which rise perpendicularly from the outerperipheral surface (40) of the housing (23).

[0084] Even when the projection part (45) is formed in the way describedabove, the casing (10) strongly tightens the projection part (45) whenthe casing (10) shrinks after the trunk part (11) and the end plate (12)are welded together, thereby enhancing sealability more thanconventional, substantially as in the above. In addition, it is possibleto prevent the decrease in workability.

[0085] Further, FIG. 8 shows an example in which the projection part(46, 47) is provided at a plurality of areas of the outer peripheralsurface (40) of the housing (23). The projection parts (46, 47) differin projection height from each other. More specifically, the projectionheight of the projection part (46) on the press-fitting side (lowerside) of the housing (23) to the trunk part (11) is made smaller, andthe projection height of the projection part (47) on the rearward side(upper side) thereof is made greater.

[0086] In this example, the projection parts (46, 47) which extendcontinuously in a circumferential direction in the outer peripheralsurface (40) of the housing (23) are arranged in multiple in the axialdirection of the housing (23). As a result of such arrangement, thenumber of press-fitting points of the projection parts (46, 47) to thetrunk part (11) increases thereby providing enhanced sealabilityFurther, since the projection height of the projection part (46) on thepress-fitting side of the housing (23) with respect to the trunk part(11) is made shorter, this makes it possible to press-fit the housing(23) to the casing (10) with relative ease while securing excellentsealability.

SECOND EMBODIMENT

[0087] In the first embodiment it is arranged such that the outerperipheral surface (40) of the housing (23) is press-fitted to the trunkpart (11) and, thereafter, the peripheral groove (42) and the projectionpart (45)(46, 47) are formed in the outer peripheral surface (40). Onthe other hand, in a second embodiment of the present invention theouter peripheral surface (40) of the housing (23) is clearance-fitted tothe trunk part (11) of the casing (10), as shown in FIG. 9. It should benoted that the Figure illustrates such clearance-fitting in anexaggerated manner.

[0088] The second embodiment is the same as the first embodiment in thefollowing points. That is to say, the peripheral groove (42) whichcontinuously extends in a circumferential direction so as to allow forshrinkage of the casing (10) due to welding at a weld area where thetrunk part (11) and the end plate (12) are welded together and theprojection part (45) which continuously extends in a circumferentialdirection at a position in close proximity to the peripheral groove (42)are formed in the outer peripheral surface (40) of the housing (23), andthe projection part (45) is so formed as to be press-fitted to the trunkpart (11) of the casing (10). Further, other arrangements are the sameas the first embodiment.

[0089] If, in the arrangement that the outer peripheral surface (40) ofthe housing (23) is clearance-fitted to the trunk part (11) or the endplate (12) of the casing (10), the peripheral groove (42) and theprojection part (45) are formed in the outer peripheral part (45) of thehousing (23), this makes it possible to perform press-fitting of thehousing (23) to the trunk part (11) with more ease, thereforefacilitating assembling work. Additionally, the trunk part (11) and theend plate (12) are welded together, with the projection part (45) of thehousing (23) press-fitted to the trunk part (11), thereby causing thecasing (10) to shrink at the position of the peripheral groove (42). Asa result, the tightening force of the casing (10) increases.Accordingly, also in this arrangement it is possible to providesealability of the same level that thermal insert does.

[0090] Furthermore, in this arrangement the housing (23) isclearance-fitted to the casing (10), as a result of which the casing(10) strongly tightens only the projection part (45) and strongtightening forces will not act on the whole of the housing (23).Consequently, the housing (23) is unlikely to undergo deformation or thelike.

[0091] It should be noted that, even in the second embodiment, theprojection part (45)(46, 47) may be modified as shown in FIGS. 5-8.

OTHER EMBODIMENTS

[0092] The foregoing embodiments of the present invention may employ thefollowing arrangements.

[0093] In the foregoing embodiments the examples in which the housing(23) serves as a partition member have been described. However, forexample, it may be arranged such that the fixed scroll (21) is attachedfirmly, as a partition member, to the casing (10) to define a high-levelpressure space and a low-level pressure space. In such a case, if aprojection part is formed around a thick part (for example, the endplate (12)) of the fixed scroll (21), this prevents strong forces fromacting on the wrap (21 b). This avoids not only refrigerant leakage dueto the deformation of the wrap (21 b) but also performance decrement.

[0094] Further, in the foregoing embodiments the description has beenmade in terms of the examples in which the present invention is appliedto the scroll compressor (1). However, the present invention isapplicable to rotating compressors of the other type such as rotarycompressors and swing compressors. Also in this case, it is advisablethat a partition member for dividing the inside of the casing (10) intoa high-level pressure space and a low-level pressure space ispress-fitted to the casing (10) at a weld area where the trunk part (11)and the end plate (12) are welded together and the partition member istightened strongly by making utilization of shrinkage of the casing (10)caused by welding.

[0095] Furthermore, in the foregoing embodiments the description hasbeen made in terms of the examples in which the projection part (45)(46,47) is formed in the outer peripheral surface (40) of the housing (23)which is press-fitted to the casing (10). However, in the arrangementthat the outer peripheral surface (40) of the housing (23) ispress-fitted to the casing (10), the projection part (45)(46, 47) is notnecessarily formed. In other words, it may be arranged such that thehousing (23) having, at the outer peripheral surface (40), no projectionpart is press-fitted to the trunk part (11) and tightening forceresulting from post-welding shrinkage is utilized. Also in this case,assembling work is easy to carry out and, besides, the casing (10)strongly tightens the outer peripheral surface of the housing (23)because of its shrinkage caused by welding, thereby making it possibleto further enhance sealability than conventional.

[0096] Further, in the foregoing embodiments the arrangement in whichthe housing (23) is press-fitted to the trunk part (11) of the casing(10) for firm attachment thereto has been descried. However, it may bearranged such that a partition member such as the housing (23) issecured firmly to the end plate (12) of the casing (10).

[0097] Industrial Applicability

[0098] As has been described, the present invention is useful forrotating compressors.

What is claimed is:
 1. A rotating compressor comprising a casing (10)housing therein: a compressor motor (30), a compression mechanism (20)which is driven by said compressor motor (30), and a partition member(23) which divides the inside of said casing (10) into a high-levelpressure space and a low-level pressure space, said casing (10) having atrunk part (11) shaped like a cylinder and an end plate (12) securedfirmly to said trunk part (11) by welding, wherein: said partitionmember (23) is so formed as to be press-fitted to said casing (10) at aweld area where said trunk part (11) and said end plate (12) are weldedtogether or in the vicinity of said weld area; and a peripheral groove(42) extending continuously in a circumferential direction for allowingfor shrinkage of said casing (10) caused by welding at said weld area ofsaid trunk part (11) and said end plate (12) is formed in an outerperipheral surface (40) of said partition member (23).
 2. The rotatingcompressor of claim 1, wherein: a projection part (45)(46, 47) extendingcontinuously in a circumferential direction at a position in proximityto said peripheral groove (42) is formed in said outer peripheralsurface (40) of said partition member (23), and said projection part(45)(46, 47) is so formed as to be press-fitted to said casing (10). 3.A rotating compressor comprising a casing (10) housing therein: acompressor motor (30), a compression mechanism (20) which is driven bysaid compressor motor (30), and a partition member (23) which dividesthe inside of said casing (10) into a high-level pressure space and alow-level pressure space, said casing (10) having a trunk part (11)shaped like a cylinder and an end plate (12) secured firmly to saidtrunk part (11) by welding, wherein: said partition member (23) is soformed as to be clearance-fitted to said casing (10) at a weld areawhere said trunk part (11) and said end plate (12) are welded togetheror in the vicinity of said weld area, a peripheral groove (42) extendingcontinuously in a circumferential direction for allowing for shrinkageof said casing (10) caused by welding at said weld area of said trunkpart (11) and said end plate (12), and a projection part (45)(46, 47)extending continuously in a circumferential direction at a position inproximity to said peripheral groove (42) are formed in an outerperipheral surface (40) of said partition member (23), and saidprojection part (45)(46, 47) is so formed as to be press-fitted to saidcasing (10).
 4. The rotating compressor of either claim 2 or claim 3,wherein said projection part (46, 47) of said partition member (23) isprovided at a plurality of areas.
 5. The rotating compressor of claim 4,wherein said projection parts (46, 47) differ in projection height fromeach other.
 6. The rotating compressor of either claim 2 or claim 3,wherein one end or both ends (45 a, 45 b) of said projection part(45)(46, 47) relative to the axial direction of said partition member(23) are formed into a tapered surface.
 7. The rotating compressor ofeither claim 2 or claim 3, wherein: said partition member (23) has athick and thin parts (43) and (44) of different thicknesses relative toa radial direction, and said projection part (45)(46, 47) is formed onan outer periphery of said thick part (43).
 8. The rotating compressorof any one of claims 1-3, wherein said end plate (12) of said casing(10) comes into axial abutment against said trunk part (11) or saidpartition member (23) and is so formed as to be clearance-fitted to saidtrunk part (11) or said partition member (23).
 9. The rotatingcompressor of any one of claims 1-3, wherein: said compression mechanism(20) is composed of a scroll type compression mechanism (20), and saidpartition member (23) is such formed that a fixed scroll (21) is securedfirmly to said partition member (23).